1. Field of the Invention
The present invention relates to graphic data processing, and more particularly, to an information storage medium including graphic data having presentation information, and an apparatus and method of processing the graphic data.
2. Description of the Related Art
Various data compression formats are used to transmit video and audio data through broadcasting or store the video and audio data in a storage medium. Among the data compression formats, Moving Picture Experts Group (MPEG)-2 transport stream (TS) multiplexes and stores video and audio data by dividing the video and audio data into packets having a predetermined size. Since graphic data, as well as video data, is displayed on a screen, the MPEG-2 TS stored in an information storage medium includes the graphic data. The graphic data roughly comprises subtitle graphic data and navigation graphic data.
The graphic data included in the MPEG-2 TS is decoded in a graphic data processing apparatus and output to a display screen. In addition to the graphic data, the MPEG-2 TS stored in the information storage medium also includes time information indicating when the graphic data is to be transmitted to a variety of buffers disposed inside the graphic data processing apparatus, and time information indicating when the graphic data of a completely composed screen is to be output to the display screen. Times indicated by the time information should be properly set so that graphic data processing may be performed efficiently. Further, a configuration of the buffers in the graphic data processing apparatus determines an efficiency of the graphic data processing apparatus. A conventional graphic data processing apparatus has a disadvantage in that the graphic data processing apparatus cannot reuse a graphic object of which a graphic screen is composed, thereby deteriorating the efficiency in the graphic data processing.